Combined electric switch and clock system



(No Model.) I O. E. BUELL. COMBINED ELECTRIC SWITCH AND OLOGK SYSTEM.

No. 248,995. Patented Nov. 1,1881.

WITNESSES: INVENTCIFH N, PETERS, Pholoiilhugnphor. Wmin mm 0.0.

UNITED STATES PATENT OFFICE.

CHARLES E. BUELL, OF NEW HAVEN, CONNECTICUT, ASSIGNOR OF TWO- THIRDS TO JAMES G. SMITH, OF HACKENSACK, NEW JERSEY, AND GEORGE W. COY, OF MILFORD, CONNECTICUT.

COMBINED ELECTRIC SWITCH AND CLOCK SYSTEM.

SPEOIFICATION'forming part of Letters Patent No. 248,995, dated November 1,1881.

- Application filed July 12, 1881. (No model.) 7

To all whom it may concern Be it known that I, CHAS. E. BUELL, acitizenof the United States, residing at New Haven, inthe county of New Haven and State of Connecticut, have invented a certain new and useful Combined Electric Switch and Clock System, of which the following is a specification.

I I The object of my invention is so to construct loand arrange or combine the apparatus of a telephone-exchange system and the regulating, controlling, or operating devices used for operating or controlling clocks by electricity,

that the two systems may be employed to gether upon the same lines and uniform time transmitted or furnished over the wires of a telephone-exchange system without interfer' ence with or from the operations of signaling to or from the various subscribersstations and of placing the various subscribers in oral communication.

My invention may be said to consist, first, in connectingthc various subscribers wires of the exchange system permanently to earth at the central office, means being provided whereby the various subscribers may be placed in oral communication without disturbing these ground connections, so that the operations of the electric-clock system will notbeinterfered 0 with; second, in arranging the apparatus at thevarioussubscribers stations of an exchange system whose central-office switch is arranged, as stated, in such a way that the continuity of the line-circuit shall not be ii'iterrupted by the act of signaling to the central oftice or of using the telephone; third, in causing the apparatus at the central station which isused for controlling or regulating the distant clocks to transmit its electrical impulses without rup- 0 turing the circuit, so that it will not interfere with the operations of signaling, which take place upon the wires of the telephone-exchange ystem. 1

The means which I have herein described for carrying out my invention consist of devices for signaling to and from the central office by changes of tension in the electric-current without breaking the circuit, of polechan ging devices for transmitting the controlling impulses of the clock system by'reversals of current without interruption of the circuit, and of artificial resistances permanently interposed in the ground-connections of the various lines, which serve to prevent the diversion of the telephonic impulses to earth when two lines are connected for oral communication.

My invention consists of various combinations and sub-combinations of apparatus, and of certain specific arrangements of the lines of telephone-exchange switch apparatus, that will be specified in the claims.

In the accompanying drawings, Figure l is a diagram showing an arrangement of circuits and apparatus that may be employed at the central station. Fig. 2 is a diagram showing an arrangement of circuits and apparatus that may be employed upon the various lines of the system. Fig. 3 is another arrangement of apparatus that may be employed at subscribers stations. Fig.4is another plan of devices that may be employed for sending the electrical impulses used in controlling or actuating the electric clocks. Fig. 5 is a plan of another arrangementof devices for the same purpose.

Referring to Fig. 1, A represents a section of a central-office switch-board, showing three diverging lines connected thereto. Each line is connected permanently to ground through a resistance, R, an independent adjustable resistance, R being interposed in the common ground connection for adjusting the general resistance to compensate for the fluctuations in the electro-motive force of the batteries or in escape, which would. if uncorrected, derange the operation of the devices worked by change of tension.

The vertical strip a is connected to a plugswitch block, g, through which any line may be connected directly to earth when it is desired to communicate orally between the ceno tral ottice and an outlying station. This earth connection is, however, not necessary, and in some cases I prefer tointroduce the telephone without shunting the resistance.

The vertical strips 1) are the line-connecting 9 5 strips, and also serve to put any line to earth through the calling-keys 717 and apparatus used in transmitting electrical impulses for vibrating bells at the stations upon the various lines. This apparatus consists of a constantlyoperating electromagnetic vibrator, A, worked by automatic make and break of the circuit ofits charging-battery l, and serving at every whole vibration to connect the anvils of the calling keys It directly to earth. This apparatus acts to send impulses of varyingtension by rapidly and intermittently short-circuiting the resistance It in the constantlycharged lines.

The call-bells at the stations consist of ordinary tap -bells, whose armatures are set into vibration by the rapidly recurring impulses, thus giving vibrating signals.

B BB are the spring-jacks,onefor each line, by which, through the divided insulated tips 0, the telephone apparatus M may be intro duced into or withdrawn from any line witlr out breaking the circuit.

For the purpose of working the an nuneiator or call-bell, I employ an electro-magnet,D, arranged upon the dift'erential plan described in my application for patent filed April 21,1879, the armature of which falls upon its back-stop when the current upon the main line, which passes through one of two differential coils upon the magnet, is regulated or adjusted so as to balance or equal the opposing magnetic effects of a local battery or generator acting in the other differential coil. The magnet here shown is a horseshoe-magnet,one leg of which is wound with a coil in local circuit with abattery,l,while its other leg is wound with a coil in the main-line circuit, which opposes the magnetic action of the local coil. The currents upon the main line are ordinarily either too strong or too weak to exactly balance the effects of the local, so that the armature is held up by the overbalanoing effects either of the main or local coil. The armature is caused to fall back and give the signal by adjusting the tension of the main-line current, so that its effects will be equal to those of the local, thus practically demagnetizing the magnet.

A signal may be given from an outlying station by means of akey, which, when depressed, shunts a regulated resistance normally in the line, and thus adjusts the tension of the linecurrent to the proper degree of strength to cause its action to balance the action of the local.

M B are the mainline or charging batteries of the various lines. As here shown, each line is provided with two batteries with opposite poles to line. These batteries are placed in the line-circuit alternately, without intermission, and the reversed currents thus charging the lines are employed for regulating or actuating the clocks.

The device for alternately introducing the batteries without npturning the circuit consists of a vibrating armaturelever, E, operated by an electro-magnet, which is in a local circuit controlled by the regulating or principal clock. The armaturedever is itself con nected to one battery, and a contact-stop, 2, which at every downward movement of the lever passes through a perforation therein, is connected to the opposite pole of the other battery. A contactspring resting upon the lever over the perforation is connected to line. INhen the armature is retracted the spring is in contact with the lever, but out of contact with the stop, thus putting one of the batteries [0 line, but breaking the circuit of the other. As the armature-lever is drawn down the spring follows it and is brought into contact with the stop and removed from contact with the lever, thus cutting out the battery first in circuit and introducing the other. As contact with the stop is made at the moment that contact with thelever is broken, and vice versa, the apparatus never breaks the main circuit. The electro magnets of these polechangers are connected in multiple, are with the wires leading from a local battery, L B, whose circuit is alternately made and broken by the pendulum I of aregulating-clock. The pendulum carries a light spring, G,which is carried into and out of contact with a metal block, d, as the pendulum vibrates, thus completing and breaking the circuit of TJ B. By this arrangement each oscillation ofthc pcndulum is accompanied by a reversal of the current upon the various main lines, and the clocks, which are provided with suitable devices for responding to these reversals, are regulated or actuated, as the case may be.

The electro-magnets controlled by battery L B might obviously be arranged in series. The arrangement shown is, however, preferable, as it gives less resistance.

I have shown here a regulating-clock which sends its regulating or actuating impulse at each vibration of the pendulum. Other forms of electricalclock regulators might, however, be used in its place, and the regulating impulse sent more or less frequently.

In Figs. 4 and 5 I have shown other appliances for producing the desired reversals in the main-line current by the action of the clock. The plans here indicated are preferable on some accounts as they require the use of but one battery to a line.

In Fig.4, M Bindicatcs a main battery whose poles are reversed by the action of a continuitypreserving reverser, such as is sometimes employed in duplex telegraphs. lVhen the armature is retracted the positive pole of the battery is connected to the line and the negative to the aunuuciator, spring-jack, and switch. When the armature is attracted the connection of the positive pole with the line is broken, and the connection with the switch and earth substituted. In the same manner the negative pole is withdrawn from earth and put to line. The path of the current in either case may be readily followed, and as the rcverser is one well known in the art it is not thought necessary to follow the circuit in detail.

The local circuit of the battery which charges M53995; r a

E M and produces the reversals is alternately made and broken by the pendulum O','as indicated.-

1 In Fig. 5 I have shown another well-known form ofpole-changer, which is actuated in both directions by electro-magnets which are alternately thrown into circuit of a local battery,

- L B, as the pendulum U vibrates and makes of the clocks, is as follows: The telephone apparatus M and the bell B are placed respectively in branch orloop circuits whose terminals are connected permanently to line and to aswitch, S, which makes contact with stops connected to line on one side or the other of the station as it is raised by its own elasticity or depressed by a treadle. \Vhen the switch is against the upper stop the telephone apparatus is short-circuited and the bell is in circuit. When the switch is depressed the bell is shortcircuited, and the short circuit of the telephone is broken, thus introducing it into the line. By this arrangement the line-circuit can under .no circumstances be broken by the switch.

This device is the same as that described in an application filed by Geo.VV. Coy, July 9, 1881, No. 37,443, and I therefore make no claim to it.

E is a resistance, which is normally in circuit. The key K serves to short circuit this resistance, and thus adjust the tension of the line-current to the strength required to cause the armature of the electro-maguet D to drop back and give a signal, in the manner before explained. This device also acts without iiiterrupting the circuit.

The form of clock device here indicated is one in which the reversed impulses serve to positively actuate the mechanism instead of merely regulating or controlling its movements, as is sometimes the case.

L represents a pivoted horseshoe magnet vibrating between the poles of two short oppositely-wound electro magnets in the line-circuit. The horseshoe-magnet is vibrated by the attractive and repulsive actions existing between it and the line electro-magnets, as the line-currents are reversed in a well-known inanner. The magnet, as shown, gives motion to adouble-ratchet movement, and causes a wheel upon a tinie-indicatin g train to rotate one step at each reversal of current caused by a vibration of the pendulum on the controlling-clock.

In Fig. 3 I have shown a two-point switch ofa well-known construction, so arranged as i to preserve the continuity of the circuit in throwing the bell and telephone into and out of circuit.

The clock device here shown is one in which the pendiil um of a power-driven train is regulated or caused to follow the movements ofthc principal clock without being positively actu-- 'fatcd'by the reversed currents upon the line. iThe pendulum here carries a coil of wire, P, which is in the main circuit, and which em- !braces and passes from end to end of two sets iof permanent stationary magnets placed with ipoles of the same name together at the mid- }dle pointin the arc of vibration. This arirangement acts in conjunction with a regulat- Eiug-clock, sending properly-timed reversals in a well-known manner, to retard or accelerate the motion of the pendulum, so as to cause it to move in exact unison with the regulatingpendulum. This being a device well known in the art, and shown here simply to indicate the fact that various forms of electrical clocks may be employed, no further description of it is necessary. It. isjust as practicable to signal the central office by throwing a resistance into circuit by breaking a normallyclosed shunt around it, and I sometimes prefer to adopt this plan instead of that shown. Signals may also be given without breaking the circuit in other waysas, forinstance, by putting the line momentarily to earth, or by introducing a local battery at the station, so as to increase the strength of current.

I do not limitmyself to any particular kind of electric clocks or regulators, as any other kind may be employed in place of those shown if it be made to send its regulatingimpulses without disturbing the continuity of the circuit; nor do I limit myself to any particular form of circuit-preserving switches for the telephone-signaling and communicating apparatus.

It is also plain that I may substitute for the automatic vibrator described other devices for sending signals from the central oftlce, and that the signal might be given by taps of the bells instead of by vibrations.

I may also use a different device for responding to the change of tension produced by the depression of a key at a subscribers station. I sometimes prefer to send signals from the central office by shunting or by breaking the normally-closed shunt of a resistance independent of the permanently-connected one.

A telephone-switch provided with the permanently-closed ground-connections, as above described, is adapted for use in place of the ordinary exchange switches now in use, and I do not limit myself, therefore, to its employment in combination only with electric-clock are therefore made to it. Many other kinds of electric clocks exist in the art that would be suitable for the purposes of this invention.

Although the ticking sound of pulsations every second upon a circuit in use for oral communication ceases to annoy the listener by habitual use, yet I contemplate the operation and adjusting ot' clocks by pulsations sent less frequently, whereby all liability to annoyance would be removed.

WVhat I claim as my invention isv 1. A telephoneexchange switch apparatus provided with permanently closed groundconnections for the several lines, for the purpose described.

2. In a telephone-exchange switch apparatus, a series of lines permanently connected to ground through a resistance, substantially as described.

3. In a telephone-exchange switch apparatus, permanently-closed ground-conuections for the several lines, containing a resistance, in combination with means for closing a shunt-circuit for each line to ground around said re- 'sistance.

the central office by change of tension without interruption of circuit, and electrical-clock apparatus provided with devices for sending, regulating, or controlling impulses by reversal of polarity without break of circuit.

7. The combination, substantially as described, with a telephone-exchange switch apparatus provided with devices for preserving the continuity of the various line-circuits during the various operations of the exchange, of a series of pole changers or reversers, one in each line, a local battery, and a regulatingclock provided with circuit-closing devices for intermittently closing and breaking the circuit of said battery, which operates the electro-magnets of the pole-changers.

S. The combination, substantially as described, upon a telephone-line, of station apparatus provided with a continuity-preserving switch for throwing the bell and telephone into and out of circuit, a continuity-preserving signaling-key for signaling to the central office by change of tension without breaking the circuit, an electric-clock apparatus operated or controlled by changes of polarity in the Iinecurrcnt, and at another station a pole changing or reversing apparatus intermittently operated by a controlling or regulating clock.

9. The combination, substantially as described, of two or more electromagnetic pole changers or reversers, one in each line, a local battery, and a regulatingclock controlling the circuit of said battery.

CHARLES E. BUELL.

Witnesses:

GEO. M. LooKWooD, G. H. Tower. 

